(CNSNews.com) – Syria’s civil war has become “increasingly sectarian,” with some attacks motivated not by strategic gain but rather by a wanton disregard for human life, a situation that is likely to worsen tensions among ethnic groups, a United Nations-commissioned report said Monday.

“It has become increasingly evident that the proliferation of foreign fighters and extremist groups has altered the character of the conflict,” said the report, compiled by an expert panel tasked to investigate all violations of human rights law in the Syrian civil war.

The report accused both pro- and anti-regime forces of abuses that could constitute crimes against humanity or war crimes – including murder, torture and attacks on non-military targets – adding that the scale and intensity of atrocities committed by regime forces were greater than those carried out by the opposition.

The panel intends to deliver to the U.N. High Commissioner for Human Rights next month a “confidential list of individuals and units believed to be responsible for crimes.”

It is recommending that steps be taken to initiate legal action, possibly by referral to the International Criminal Court. As Syria is not a party to the treaty that established the Hague-based tribunal, referral would have to come from the U.N. Security Council.

The conflict between President Bashar Assad’s regime and those seeking to end it has focused attention on the country’s fragmentation along, ethnic, tribal and religious lines.

Assad’s Allawite sect is a minority within Shia Islam, and the 2.3 million-strong Christian minority is reported largely to side with the Allawites, fearful of an Islamist takeover. The U.S. and rebels have accused Shi’ite Iran and the Lebanese Shiite terrorist group Hezbollah of involvement in support of the regime.

On the other side of the conflict, most anti-regime fighters are from Syria’s Sunni majority, among them the Qatar-backed Muslim Brotherhood, boosted by radical Salafis, including foreign fighters from countries including Libya, Lebanon, Iraq, Egypt, Saudi Arabia and Tunisia.

Kurdish nationalists, who control sizeable areas of territory in Syria’s northeast, add another element.

Monday’s report, which covers a six-month period up to the middle of January, provides a glimpse into the way the conflict is worsening the sectarian fissures – evidently by design in some instances.

“There has been an increase in attacks in which no parties claim responsibility and which do not appear to have any military or strategic objective, beyond their primary purpose to spread terror among the civilian population,” it said.

“Of particular concern are attacks that may foment sectarian tensions. Such attacks are not motivated by any military or strategic gain, but rather by a wanton and menacing disregard for human life.”

“More than ten incidents [during the reporting period] were documented in which improvised explosive devices, whether body- or vehicle-borne, were set off in minority neighborhoods or in the vicinity of religious sites,” it said.

The panel referred to pro-regime militia using sectarian affiliation as they seek to fill their ranks, possibly including children among recruits, and said wounded people are sometimes refused hospital treatment on sectarian grounds.

It said minority communities, notably Allawites and Christians, had formed armed self-defense groups to protect their neighborhoods, in some cases armed and equipped by the regime.

Radicals, foreign support

The report also highlighted the influence of foreign combatants and foreign sponsorship.

“Another key concern is the radicalization of the conflict owing to the growing presence of foreign fighters,” it said, noting that their presence is contributing to an overall radicalizing trend among the anti-Assad rebellion.

“The escalation of violence and increasing intervention of external sponsors has also led to radicalization among the anti-government armed groups, and the proportion of fighters with Salafi inclinations has augmented including local and foreign extremists.

“The financial support provided by donors not only strengthened Salafi factions but also pushed mainstream insurgents toward joining them due to their better ability to provide them with the necessary logistical supplies.”

The report said among these groups the Al-Nusra Front stood out due to superior levels of operational effectiveness and the “use of more aggressive tactics clearly benefiting from better financial support.”

Al Nusra is the group designated by the U.S. last December as a foreign terrorist organization. The State Department said it was an alias for al-Qaeda in Iraq.

The report also listed some of the weapons being in the conflict, including bombs, cluster munitions, shoulder-launched surface-to-air missiles, anti-tank missiles, artillery, mortars, assault rifles and vehicle-mounted heavy machine guns.

The panel expressed concern about the implications of the growing sectarianism for Syria’s future.

“The destructive dynamics of the civil war not only have an impact on the civilian population but are also tearing apart the country’s complex social fabric, jeopardizing future generations and undermining peace and security in the entire region,” its report said.

The U.N. estimates that up to 70,000 people have been killed since the anti-Assad revolt began in mid-March 2011, and that more than one million Syrians have fled the country.